Many portable electronic devices today implement multimedia acquisition systems that can be used to acquire audio and video information. Many such devices include audio and video recording functionality that allow them to operate as handheld, portable audio-video (AV) systems. Examples of portable electronic devices that have such capability include, for example, digital wireless cellular phones and other types of wireless communication devices, digital video cameras, etc.
Some portable electronic devices include one or more microphones mounted in the portable electronic device. These microphones can be used to acquire and/or record audio information from an operator of the device and/or from a subject that is being recorded. It is desirable to be able acquire and/or record a spatial audio signal across a full or entire audio frequency bandwidth.
Beamforming generally refers to audio signal processing techniques that can be used to spatially process and filter sound waves received by an array of microphones to achieve a narrower response in a desired direction. Beamforming can be used to change the directionality of a microphone array so that audio signals generated from different microphones can be combined. Beamforming enables a particular pattern of sound to be preferentially observed to allow for acquisition of an audio signal-of-interest and the exclusion of audio signals that are outside the directional beam pattern.
When applied to portable electronic devices, however, physical limitations or constraints can limit the effectiveness of classical multi-microphone beamforming techniques. The physical structure of a portable electronic device can restrict the useable bandwidth of the multimedia acquisition system, and thus prevent it from acquiring a spatial wideband audio signal across the full 20-20K Hz audio bandwidth. Parameters that can restrict the performance or useable bandwidth of a multimedia acquisition system include, for example, physical microphone spacing, port mismatch, frequency response mismatch, and shadowing due to the physical structure that the microphones are mounted in. This is in part because the microphones may be multi-purpose, for example, for multimedia audio signal acquisition, private mode telephone conversation, and speakerphone telephone conversation.
Accordingly, it is desirable to provide improved portable electronic devices having the capability to acquire and/or record a spatial wideband audio signal across a full audio frequency bandwidth. It is also desirable to provide methods and systems within such devices that can allow a portable electronic device to acquire and/or record a spatial wideband audio signal across a full audio frequency bandwidth despite physical limitations of such devices. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.